<!DOCTYPE HTML>
<html>

<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>while</title>
  <script type="text/javascript">
    var mynum = 1; //mynum初值化数值为1
    while (mynum <= 5) {
      document.write("数字:" + mynum);
      mynum = mynum + 1;
    }
  </script>
</head>

<body>
</body>

</html>